On Monday, March 9, 2009 the S&P 500 finished trading at its post financial crisis closing low of 676.53. Since then the index hasn't crossed below that point, gaining more than 200% and building into a long-term bull market that will turn five on Sunday.

"It has been a bull market that nobody really enjoyed," says Chris Bertelsen chief investment officer at Global Financial Private Capital. Of the 479 current S&P stocks stocks traded in 2009, 473 are positive since the the bottom, 63% of them are up at least as much as the whole index. Big winners include , and . , and are among the losers.

Noting that the past year an a half have provided particularly slim pickings for value oriented investors like him, Bertelsen added, "everybody was worried about a pull back so they didn’t participate to the extent, in hindsight, they would have wanted to. Everyone was waiting for an opportunity like a flash crash and they never got it.”

The question now is will they get it soon? Historical precedent points to yes -- maybe.

According to Sam Stovall, chief equity strategist at S&P Capital IQ, less than 30% of post-WWII bull markets have celebrated their sixth birthdays, meaning a draw down in the next 12 months is statistically likely. "Five years is a long time for a market to expand without having a major drop,” says Richard Sylla a professor of financial history at New York University's Stern School of Business.

The 2.7% drop in January didn't cut it for value and growth investors in search of cheap quality, nor did the blip Monday in response to the situation in Ukraine. But both short-term declines could be for-tellers of bigger drops to come. According to Bertelsen some evidence suggests that January downturns tend to signal a laggard year ahead. And wars (or the threat of war), says Sylla, generally result in stock markets declines. "Suppose the current situation in Ukraine turns into something a little nastier, that could be a problem."

In school we learn that jobs created to service WWII pulled the U.S. out of the Great Depression. While this is true in a broader sense, the equity markets were coming from such lows that Sylla explains that it took 25 years for the market to reach a new high after the Depression. "The Dow peaked in September 1929 and took until 1954 for the Dow to get back." So relative to the long recovery after the Depression, the five years and seven months it took the S&P to rise above it's pre-financial crisis high was astounding.

Through the 1950s and early '60s markets continued to climb before stagnating in 1966 due to inflation. Markets did not start moving again until 1982 and kept climbing until October 19, 1987, responding to Reagan era tax cuts, economic expansion and, perhaps most fundamentally, inflation control under Paul Volcker at the Federal Reserve. The 1987 crash converted the market to a bear, as stocks shed almost 23% in a single day. It took about two years for markets to regain previous highs, and then from 1990 to 2000 stocks, as well as gross domestic product, gained largely uninterrupted. Stocks then pulled back as the dot com bubble deflated, before growing for another five years, from 2002 to the 2007 financial crisis.

"Certainly the bull market that we enjoyed in the '80s was born out of the same type of recessionary environment [as the financial crisis], although it wasn't a liquidity crisis. It was born out of the first energy shocks of the late 1970s and it was pretty enjoyable run until October of 1987," reflects Bertelsen. "What we saw in the 1990s was probably the most euphoric of the bull markets in the sense that it was enjoyed by everybody."

Mark Yusko, CIO of Morgan Creek Capital Management, points out that equity prices go in cycles and "tend to spend very little time at fair value." He explains that late economic historian Charles Kindleberger espoused a theory that market cycles have five stages: bust, revulsion, displacement, boom and euphoria. “Happy birthday," declares Yusko, "What’s interesting if you look back in time is that normally we have five year periods like this every 7 years, when they coincide with a 14 year innovation cycle we end up with speculative bubble tops.”

Rather than random volatility, Yusko sees market peaks and valleys as at least partially guided by game changing new products developed by young innovators. Mainframe computers, personal computers and now mobile devices, he explains, all led to market booms. But what goes up must come down. According to Yusko the current market is hovering somewhere between boom and euphoria, so a bust could be imminent.

Economic indicators also show potential to bring stocks down. While the U.S. economy seems to be expanding, growth is sluggish. Sylla observes, "A lot of people wonder why we have had a five year bull market given that our economy still has above normal unemployment and is growing very slowly."

In response to the economic weakness following the financial crisis the Federal Reserve began an aggressive asset purchase program unlike anything that had been seen since the Great Depression. In December 2013 the central bank began drawing down its bond buying. While markets initially waved off the news, Sylla doesn't believe the story ends there. “Tapering means your still buying an unusual number of bonds every month just not as many as you did last month," he says. "In other words, the Fed has almost announced that it is weakening one of the underpinnings of the bull market. That is not going to make stocks go down today or tomorrow but at some point.”

Add in elevated and unsustainable corporate earnings and Sylla believes markets are heading for at least a slowdown. And the professor's forecasting track record it good. He called the bear market of 2000 and, unlike the folks Bertelsen says missed the bull, Sylla has enjoyed the run.

"I’ve read over three centuries of financial history," says Sylla. Conceding, "Nobody can ever be sure about these things."